Susan Harris (Julie Christie) is in a troubled marriage with Alex (Fritz Weaver), a scientist. When Alex moves out of their luxurious home, which is run by the super computer "Proteus" that Alex created, Susan becomes trapped by "Proteus", who is becoming more powerful by the day. Locked in her home with no communication with the outside world, Susan tries everything she can to free herself from the prison that she's in, but to no avail. "Proteus" inseminates Susan in a "rape" like fashion, and in the end, a part human, part super computer "baby" emerges from an incubator pod in the basement.